I'm a long time user of Acrobat and XI is frustrating me. I routinely create .pdf files for inclusion in larger reports that I would bookmark using the "import bookmarks" function.. Has this functionality been removed from XI Pro?

Acrobat never did this, so far as I know. Of course, I'm not saying you didn't do this! My conclusion is that you had an add-in to Acrobat that did this. If you can find what the add-in was you can probably install and use it (possibly a new version of it).